Spectroscopy from the Hubble Space Telescope Cosmic Origins Spectrograph of the Southern Nova-like BB Doradus in an Intermediate State
Szkody, Paula; Sion, Edward M.; Godon, Patrick; Hubeny, Ivan; Gänsicke, Boris T.; Pala, Anna F.; de Martino, Domitilla; Rodríguez-Gil, Pablo; Toloza, Odette
United States, United Kingdom, Italy, Spain
Abstract
We present a spectral analysis of the spectrum from the Hubble Space Telescope Cosmic Origins Spectrograph (HST/COS) of the southern VY Scl nova-like variable BB Doradus, obtained as part of a Cycle 20 HST/COS survey of accreting white dwarfs (WDs) in cataclysmic variables. BB Dor was observed with COS during an intermediate state with a low mass accretion rate, thereby allowing an estimate of the WD temperature. The results of our spectral analysis show that the WD is a significant far-ultraviolet (FUV) component of the spectrum with a temperature of about 35,000-50,000 K, assuming a WD mass of 0.80 {M}⊙ ({log}(g)=8.4). The disk, with a mass accretion rate of ≈ {10}-10 {M}⊙ {{yr}}-1, contributes about 1/5 to 1/2 of the FUV flux.